1. Field of the Invention
This invention relates to a novel heating device comprising a burnt cylindrical support core of ceramics and heater element(s) disposed around the core in which heater element(s) and a heat-generating resistor pattern are hermetically sealed in a burnt ceramic sheet body. The support core is adapted so that articles to be heated such as an electric soldering iron and a hair curling device in which heating over cylindrical configuration is necessary are combined with the device.
2. Prior Art
Various kinds of heater elements are known in the art and are used in a wide range of heating applications. A most simple and popular heater is one provided with a nichrome wire upon an insulating body. Such a heater element provided with the nichrome wire, with its peculiar features, requires rather considerable amounts of electric power consumption. Moreover, since the nichrome wire is exposed to the air, the heating of the wire always accompanies oxidation thereof. This causes deterioration in a relatively short time. In addition, under some environments, the nichrome wire is subjected to a chemical erosion which also reduces its useful life. While heater elements using a nichrome wire as a heat-generating medium do have the advantage that they can be manufactured at a low cost and the quantity of heat produced therefrom is relatively large, breakage, oxidation, etc. are associated with its use which often outweighs its initial low cost.
Another prior art heater element uses a conductive resin as a heat-generating medium in which the heat is spread by the resin. However, the quantity of heat is reduced with these heater elements due to the comparatively low heat-resistance of the resin used which limits the applicabilities thereof. These types of heaters are further limited in their use because of their high manufacturing cost.